<template>
  <div class="bottom-menu">
    <check-button class="select-all" :is-check="isSlectorAll" 
    @click.native='checkClick' />
    <span>全选</span>
    <span class="total-price">合计：￥{{totalPrice}}</span>
    <span class="buy-product">去计算 {{cartLength}}</span>
  </div>
</template>

<script>
import CheckButton from "@/components/content/checkButton/CheckButton";
import { mapGetters } from "vuex";

export default {
  data() {
    return {};
  },
  computed: {
    ...mapGetters(["cartList"]),
    totalPrice() {
      return this.cartList
        .filter(item => {
          return item.checked;
        })
        .reduce((prev, next) => {
          return prev + next.price * next.count;
        }, 0)
        .toFixed(2);
    },
    cartLength() {
      return this.cartList.filter(item => item.checked).length;
    },
    isSlectorAll() { // 决定是否全选
      if(!this.cartList.length) return false;  // 购物车为空，直接false
      // 三种方案：filter、find、for循环
      return !this.cartList.find(item => !item.checked); // 如果有没被选中的商品，取反返回false
      // 1、filter方法
      // return !this.cartList.filter(item => !item.checked).length
      // 2、for循环
      // for (let item of this.cartList) {
        //   if(!item.checked){
          //     return false;
      //   }
      // }
      // return true;
    }
  },
  methods: {
    checkClick(){
      if(this.isSlectorAll){ //全部选中了，map、forEach都可以
        this.cartList.map(item => item.checked = false)
      }else{ // 部分或全部不选中
        this.cartList.forEach( item => item.checked = true )
      }
    }
  },
  components: {
    CheckButton
  }
};
</script>

<style lang='scss' scoped>
.bottom-menu {
  width: 100%;
  height: 44px;
  background-color: #eee;
  position: fixed;
  bottom: 50px;
  left: 0;
  box-shadow: 0 -2px 3px rgba(0, 0, 0, 0.2);
  font-size: 14px;
  color: #888;
  line-height: 44px;
  padding-left: 35px;
  box-sizing: border-box;
}

.bottom-menu .select-all {
  position: absolute;
  line-height: 0;
  left: 12px;
  top: 13px;
}

.bottom-menu .total-price {
  margin-left: 15px;
  font-size: 16px;
  color: #666;
}

.bottom-menu .buy-product {
  background-color: orangered;
  color: #fff;
  width: 100px;
  height: 44px;
  text-align: center;
  line-height: 44px;
  float: right;
}
</style>